Method of and apparatus for preparing in the pure state acetone, ethyl alcohol, and butyl alcohol from watery solutions



Oct. 12, G RE|CHARDT METHOD 0F AND APPARATUS FOR PREPARING 1N THE PURE STATE ACETONE,

ETHYL ALCOHOL, AND BUTYL-ALCOHOL FROM WATERY SOLUTIONS Filed May 9, 1933 co/L CONUVENSER ALCONL COI. UMN

Patent-ed oct. 12, `1937 u I 2,095,347`

UNITED sTATEs PATENT oFElcE METHOD OF AND APPARATUS FOR PRE- PARING IN THE PURE STATE ACETONE, ETHYL ALCOHOL, AND BUTYL ALCOHOL FROM WATERY SOLUTIONS Georg Reichardt, Grimma, Germany, assgnor to the firm Maschinenbau-Aktiengesellschaft Golzern-Grimma, Grimma, Germany Application May 9, 193s, serial No. @10,190

, In Germany May 12, 1932 8 Claims. (Cl. 202-42) My invention relates to the preparation, in butyl alcohol and water, and waterfree butyl althe pure state, of acetone, ethyl alcohol and butyl cohol. i y alcohol from watery solutions such as mash and This operation can only be performed if the the like. residual liquid separates into two layers after It is an object of my invention to improve the the acetone has been distilled away, but this sepmethod of such preparation and to provide an aration or decomposition does not occur in many improved apparatus for performing it. cases, for instance, if theV initial product is a The practicability of-the existing methods for mash, i. e., a solution obtained by the action of y preparing acetone, ethyl alcohol and butyl almicro-organisms on carbohydrates and normally 10 cohol from a watery solution of all three compocontaining about 95% water. For the treatment 10 nents, and their economy, are largely determined of such solutions which is of particular technical by the composition of the mixtures to be treated. importance, the aforesaid method is impractical This is due to the solubility and vapor pressure of but methods have also been proposed for obtainthe system butyl alcohol and water, and to the ining acetone, ethyl alcohol and butyl alcohol from f iiuence exerted by the presence of acetone and such principally watery solutions.' In the older ethyl alcohol whose miscibility with butyl. alcohol methods, acetone, ethyl alcohol, butyl alcohol and and water is unlimited. On the other hand, the Va certain portion of water are continuously dismiscibility of butyl alcohol and water is limited tilled away from the watery initial solution in a and. under certain conditions of concentration column and the distillate vapors are subjected t0 causes the formation of separate layers of the rectification in another column directly. By these 20 two components. The question whether the formethods, crude acetone concentrate containing mation'of such layers can be. utilized for the ethylalcohol, and a mixture of butyl alcohol and separation, is technically and commercially imwater are obtained whose composition is about Portant that of the azeotropic mixture. This mixture 25 The percentage of butyl alcohol and water is after condensation decomposes into two layers 25 important for the distillation of the mixture bethe lower, watery one of which returns into the cause the two components form a mixture of column. The upper layer consists substantially minimum'boiling point, and this mixture can of butyl alcohol and 15% water. Thermixture be separated from the component which is preswhich forms the upper layer, and thel crude ace- "0 ent in excess, by distillation. The residue will tone, with its content of' ethyl alcohol, are the be water or butyl alcohol,l in accordance with the products of the method.

composition of the initial mixture. Ethyl alcohol cannot be obtained in continuous The azeotropic mixture of water and butyl aloperation. In mashes of normal composition, it cohol contains about 37% water and its boiling is present in small quantities only and is obtained point is 92.3 centigrade. After condensation, the as impurity of the acetone as well as of the butyl mixture separates into two layers in conformity alcohol fraction. Both distillates, for preparing with the solubility conditions. pure acetone or butyl alcohol, are fractioned by The methods of uninterrupted separation of separate and non-continuous processes, with or acetone, ethyl alcohol, butyl alcohol and water without'the addition of chemicals. This method 4o are based on definite conditions of concentrais uneconomical on account of high loss and high tion in the initial mixture. Thus, solutions which steam consumption. decompose. after the acetone has been eliminated, 'Ihe methods referred to and aiming at the may be worked in a manner known in the art, direct separation of acetone from the initial mixby first distilling the acetone away from the ture, have the drawback Vthat the gaseous fer- 45 initial solution in a fractionating column of usual mentation products which are-present in considtype. The formation of layers which is now erable quantities in mashes, for instance, carbon brought about, permits decomposing the residual dioxide and hydrogen, get into the acetone fracliquid into a component consisting mainly of tion, interfere with its rectification and cause butyl alcohol, and another component of rmainly loss. 60 watery character. The two components or layers The drawbacks of the aforesaid old methods are rectified separately in` two more columns. are eliminated according to my invention and The, ethyl alcoholis obtained from the watery pure acetone, ethyl alcohol and butylalcohol are component while the butyl alcohol component obtained from thin watery solutions such as is decomposed into an azeotropic mixture of mashes, etc., it being understood that the term 55 mash" as employed herein refers to a butyl alcohol-acetone fermentation mash.

A plant in which my method is performed, will now be briefly described with reference to the accompanying drawing in which the plant has been illustrated diagrammatically by way of ex ample.

The initial product, mash or the like, i. e., a mixture of water, acetone, ethyl alcohol and butyl alcohol, is distilled in the first column I to separate them from the bulk of the water in the solution. The water is discharged at the base of the rst-column and flows through a heat exchanger 6 where it gives up its heat to the solution to be distilled, or to some other liquid.

'I'he distillate vapors which may be concentrated by reducing their percentage of water, are liquefied in a condenser and gas separator 5, 9 where non-condensable gases, if any, are eliminated. 'Ihe hot condensate from the condenser 5 is immediately conducted to the recticationplant in which the mixture is decomposed as follows:

If the initial product is mash, the principal constituent of the crude condensate is butyl alcohol which is separated in the second or butyl column I3. In this column, acetone and ethyl alcohol, with a small percentage of water and butyl alcohol, are rectified and distilled away from the column I3 in upward direction, while butyl alcohol and water, being higher-boiling constituents, are concentrated in downward direction and finally, substantially free from acetone and ethyl alcohol, collect in a container 26, with a closed bottom plate 24, at the centre of the column I3.

In this container the liquid decomposes into an upper layer consisting principally of butyl alcohol, and a lower, principally watery layer. The upper layer is discharged into the lower portion of the column I3 below the bottom plate 24, by an overow pipe 21. In this lower portion of the column, the liquid which contains but little Water, is decomposed by rectication into an azeotropic mixture of butyl alcohol and water, and waterfree butyl alcohol. 'I'he vapor of the mixture is returned to the container by a pipe 28 and the waterfree butyl-alcohol vapor, or the butyl alcohol in liquid condition, is conducted to a condenser 30 through pipe 29.

'I'he lower layer of liquid in the container is a saturated solution of butyl alcohol in water, with only small quantities of ethyl alcohol and acetone. 'I'his saturated solution is returned to the rst column I through a pipe 3| but may also be de,- livered to the fourth or ethyl-alcohol column 6I,

'Ihe method as described has important admoved in liquid condition and without expenditure of heat for its evaporation. Condensers and separators for decomposing or liquefaction of the azeotropic butyl-alcohol-water distillate are not required. The latent heat of the butyl-alcohol water vapor which ilows into the container 26 through pipe 20 from the lower portion of column I3, is directly utilized for heating the upper portion of the column. 'I'he liquid which'decomposes into two layers in the container 26, is delivered to the subsequent stages without loss of heat. At the head of the butyl alcohol column I3, the acetone and the ethyl alcohol, as mentioned, are distilled away with traces of butyl alcohol and water. Normally, this mixture which is decomposed in the subsequent stages of the process, is only about of the crude distillate from mash of normal composition. Therefore the preparation of pure acetone and ethyl alcohol according to my method requires a smaller plant and lower operation cost than the old methods in which the butyl alcohol is separated only in the last stage.

'I'he distillate from the upper portion of the butyl alcohol column I3 is delivered to the third or acetone column 39 directly or through a condenser 34. In the column 39, the acetone is separated and rectified and delivered to a condenser 5I in vapor condition. A portion of the condensate from 5I is returned to the column 39 through pipe line .54 while the balance is discharged through pipe 60 as the nishedproduct. If required, the distillate can be subjected to further rectication.

From the bottom of the acetone column 39, the acetone-free residue is conducted to the ethyl alcohol column 6I where the ethyl alcohol is distilled away and rectified. The condensers 63, 64 of this column deliver high-grade ethyl alcohol. The residual water quite free from valuable materials, ows from the lower portion of the column 6I. Only a small percentage of butyl alcohol gets into the ethyl-alcohol column 6I with the distillation residue from the acetone column 39 and the butyl alcohol is concentrated in a definite zone. The concentrated mixture collects in a container 'I4 with a bottom plate 13 where it decomposes into two layers. The upper layer is extracted through pipe l5 and delivered to the butyl alcohol column I3 at its top.

It will be understood from this brief description that only pure products are obtained by the cycle. The water from the initial product, slop, singlings water, etc., are discharged free from acetone, ethyl and butyl alcohol.

If there are still other substances in the crude mixture or in the mash, the purication method may be extended with respect to these. For instance, if higher alcohols are present, the product from the base of the butyl alcohol column I3 is directly delivered to a column (not shown) in which the butyl alcohol is continuously distilled away from the higher-boiling components. Similarly, if impurities such as higher ketones are present in the ethyl alcohol from the plant,

' the alcohol may be purified by further rectication. y

Intermediate distillates may be treated chemically, for instance, with alkaline substances from reservoirs I5, I6.

The plant, which has been briey described for illustrating my method, will now be described in full detail.

The watery solution which is the initial product, is stored in a reservoir 2 from which it is conductedto the plant througha pipe 4. Instead of a gravity reservoir, -a pump 3 may be provided which conveys the liquid from some lowlevel reservoir, such as a fermentation vat (not shown) and delivers it to the gravity reservoir 2 through pipe line 400, which the gravity pipe 4 402 delivers the liquid to first column I where it crude distillate from the top ofthe condenser 5,A the liquid ows to a heat exchanger 6 through pipe 403. 'Ihe heat exchanger is supplied with hot 1"quid from the base of column I through a'pipe 'I'he liquid ir. the pipe 'l which may be slop is entirely without acetone, ethyl and butyl alcohol and delivers a portion of its heat to the initial liquid or mash.

40| or to a pipe 402 to.

The base of column I is heated by steam. From its top where the crude distillate is concentrated, a spirit pipe 8 extends to the condenser 5, with its gas separator 9. The vapor from the column I is condensed in and non-condensable gas is separated in 9 and discharged through a pipe I0. A portion of the condensate from condenser 5 and separator 9 is returned to the column I through pipe Il and pipe ,IIO, respectively, and the balance is conducted to the butyl alcohol column I3 through pipes I2, |20 and I2I, respectively. 'A neutralizer 22 is in-v serted between the pipes |20 and I2I. I4 are regulating valves in the pipes I2 and |20.

For neutralizing volatile acids, lye from the reservoirs I5 and I6 may -be conducted to the columns or to intermediate distillates which arev free from carbon dioxide. The lye may be conducted directly to the individual columns I, I3, 39 and 6I, through pipes I1, I8, I9, 20 and 2I, respectively, with suitable shut-oil valves, or it may be conducted to any desired number of neutralizers such as 22 through pipe 23.

The mixture delivered to the butyl alcohol column I3 is decomposed in the top portion of the column, above the bottom plate 24. The decomposition results in the formation kof a distillate consisting mainly of acetone and ethyl alcohol and containing but little butyl alcohol and water, and a. mixture of butyl alcohol and water which is substantially free from acetone and ethyl through spirit alcohol. This mixture is vdelivered to the container 26 through pipe 25. Here, it forms two layers. The upper llayer which is rich in butyl alcohol, is conducted to the indirectly heated base of the column I3 through a pipe 21, and the butyl alcohol is dehydrated by distilling away the azeotrcpic mixture of butyl alcohol and water. At the same time, any traces of acetone and ethyl alcohol are eliminated from the butyl alcohol. The distillate vapor from the lower portion is conducted to the upper part of the column by a spirit pipe 28 on top of the bottom plate to the container 26. The waterfree butyl alcohol is conducted to the condenser 30 through a pipe 29 from the bottom of column I3. The lower layer of the liquid in the container 2'6 returns to the iirst column I through a pipe 3l with a regulating valve 32. From the top of the butyl alcohol column I3, the distillate vapor is conducted to a condenser 34 pipe 33, and from this partly to a separator 35 with a vent pipe 36. The condensate from 34 and 35 partly returns to column I3 through pipes 31 and the balance is conducted to the acetone column 39 through pipes 38. 40 are regulating valves in the pipes 38. A by-pass pipe 4I connects the spirit vpipe 33 directly to the acetone column so that when the valve 42 is closed and the valve 43 opened, the distillate vapor flows directly to column 39. The rectified acetone vapor is conducted to a condenser 5I through a spirit pipe 50, with a separator 53 and vent pipe 52. The acetone-free residual liquid is discharged from the base of the column 39 andconducted to the ethyl-alcohol column 6I, through a pipe 44. For bringing about a more effective separation, the acetone column 39 has an intermediate condenser 45. A partition 46 (closed bottom plate) in the column causes the vapor to leave the column through pipev 41 and to ilow through the intermediate condenser 45.' After having been separated from the condensate which is rich in high boiling-components, the vapor is returned to the column 39 above the partition 46 to the column 6I through pipe 66.

l coil, through a pipe 61, and high-grade `column I3 through a pump continuously distilling a i 59 while condensate may be discharged through pipe60. e

The acetone-free residue through pipe 44 gets into the steam-heated ethyl-alcohol column 6I from which the rectied vapor is discharged through the spirit pipe 62 and condensed in the condenser 63 and the separator 64, with vent pipe 65. A portion of the condensate is returned From the condenser 63, a portion of the condensate isI conducted to the coil 56 which is in fact a double delivered from the second coil through pipe 68 and valve 69. A pipe which is connected to the separator 64, returns condensate to the acetone column 39. Through a pipe 1I, this portion of the distillate can I through, pipe 59. charging A pipe 12 serves for disthe condensate, if required.

39 through pipes 54,V

alcohol is be returned to column The small quantity of butyl alcohol which gets into the column 6I through pipe 44, is concentrated in the central portion of the column where a container 14 with a bottom plate 13 is provided. The liquid which collects in the container 14, decomposes into two layers of which the upper one, rich in butyl alcohol, is permanently drained through pipe 15 and conveyed to the butyl alcohol (not shown). The lower, principally watery, layer ilows through pipe 16 into the lower dealcoholizing portion of column 6I which is below the bottom plate 13. The distillate vapor from this lower portion of the column is delivered to the container 14 through a spirit pipe 11 above The singlings waterA flows from the base column 6I through pipe 18.

if it is desired to work the liquid of the lower layer in container 26 in the column 6I., a connection may be established between 426 and 6I through pipes 3l and 19, with suitable shut-off valves.

It will be understood that my method is direct and continuous.

I claim:

1. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol and butyl alcohol from mashes of butyl alcoholacetone-ethyl alcohol fermentation comprising butyl alcohol-acetoneethyl alcohol-water mixture from said mashes, separating the condensate by further distillation into a vmixture of vapors' rich in acetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said'liquid into an upper layer rich in butyl alcohol and a lower layer rich in water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeotropic mixture of butyl alcohol and water, and returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquidv into said upper and lower layers.

2. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol 0f the and butyl alcohol from mashes of butyl alcoholacetone-ethyl alcohol fermentation comprising continuously distilling a butyl alcohol-acetoneethyl alcohol-water mixture from said mashes, separating the condensate by further distillation into a mixture of vapors rich in acetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said liquid into an upper layer rich in butyl alcohol and a lower layer rich in water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeotropic mixture of butyl alcohol and water, returning said lower layer rich in water to said rst distillation stage, and returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers.

3. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol and butyl alcohol from mashes of butyl alcoholacetone-ethyl. alcohol fermentation comprising continuously distilling a butyl alcohol-acetoneethyl alcohol-water mixture from said mashes, separating non-condensable gas from the condensate, separating the condensate by further distillation into a mixture of vapors richinacetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said liquid into an upper layer rich in butyl alcohol and a lower layer rich ln water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeotropic mixture of butyl alcohol and water, returning said lower layer rich in water to said rst distillation stage, and returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers.

4. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol and butyl alcohol from mashes of butyl alcoholacetone-ethyl alcohol fermentation comprising continuously distilling a butyl alcohol-acetoneethyl alcohol-water mixture from said mashes, separating the condensate by further distillation into a mixture of vapors rich in acetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said liquid into an upper layer rich in butyl alcohol and a lower layer rich in Water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeothropic mixture of butyl alcohol and water, returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers, separating the acetone by a third distillation stage from the mixture rich in acetone and ethyl alcohol, rectifying the acetone, and separating in a fourth distillation stagethe acetone-free liquid residue into high grade ethyl alcohol and water.

5. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol and butyl alcohol from mashes of butyl alcoholacetone-ethyl alcohol fermentation comprising continuously distilling a butyl alcohol-acetoneethyl alcohol-'water mixture from said mashes, separating the condensate by further distillation into a mixture of vapors rich in acetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said liquid into an upper layer rich in butyl alcohol and a lower layer rich in water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeotropic mixture of 'butyl alcohol and water, returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers, separating the acetone by a third distillation stage from the mixture rich in acetone and ethyl alcohol, rectifying the acetone, separating in a, fourth distillation stage the acetone-free liquid residue into high grade ethyl alcohol and water, and returning any butyl alcohol remaining from and enriched in said fourth distillation stage to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers.

6. A process for directly and continuously preparing in the pure state acetone, ethyl alcohol and butyl alcohol from mashes of butyl alcoholacetone-ethyl alcohol fermentation comprisingy continuously distilling a butyl alcohol-acetone ethyl alcohol-water mixture from said mashes, separating the condensate by further distillation into a mixture of vapors rich in acetone and ethyl alcohol and into a butyl alcohol-rich liquid, separating said liquid into an upper layer rich in butyl alcohol, and a lower layer rich in Water, rectifying said upper layer rich in butyl alcohol to produce water-free butyl alcohol and a vaporous azeotropic mixture of butyl alcohol and water, returning said lower layer rich in water to said rst distillation stage, returning said vaporous azeotropic mixture to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers, separating the acetone by a third distillation stage from the mixture rich in acetone and ethyl alcohol, rectifying the acetone, separating in a fourth distillation stage the acetone-free liquid residue into high grade ethyl alcohol and water, and returning any butyl alcohol remaining from and enriched in said fourth distillation stage to the process at the point of separation of said butyl alcohol-rich liquid into said upper and lower layers.

7. In apparatus for lthe continuous preparation of acetone, ethyl alcohol and butyl alcohol from a -watery solution containing the same, in combination, a rst distillation column for concentrating the solution by eliminationof surplus water and non-condensable vapors from the solution, .a second distillation column for receiving the concentrated solution and distilling therefrom the acetone and ethyl alcohol, a decanting chamber within'said'scond distillation column for receiving the resulting mixture of butyl alcohol and water, a conduit connected with said chamber for conducting the upper layer of said last named mixture, containing principally butyl alcohol, to the part of 'said second column below said chamber, a conduit connected with said chamber for conducting the lower layer of said last named mixture, containing principally water to said first column, and a third distillation column for receiving the distillate of acetone and ethyl alcohol from said second column for distilling 01T the acetone therefrom.

8. In combination with the apparatus as described in claim '7, a vapor conduit connecting the portion of said second column below said decanting chamber with said decanting chamber.

GEORG REICHARDT. 

